19 



The specific gravity curve of this turpentine, figure 9, is similar in 

 general respects to that of the gum turpentine of Table 1. It is seen, 

 however, that about 70 per cent of the oil has a specific gravity wit liiu 

 a variation of 0.0025 or between 0.8665 and 0.8690, a difference of 0.29 

 per cent. Above this the curve turns sharply to the right and ends at 

 80 per cent ; the balance of 20 per cent was a heavy residue which was 

 left in the flask. It seems, therefore, from the figure that this tur- 

 pentine contained 70 per cent of a pure oil. 



The index of refraction curve, figure 10, confirms this conclusion. 

 Here we find that up to 70 per cent the index of refractions varied from 

 1.4701 to 1.4735, a difference of 0.0034, which is 0.23 per cent, or 

 slightly less than the variation in the specific gravity over 92J per 

 cent of the gum turpentine. The distillate beyond 70 per cent was of 

 a complex character, as is shown by the shape of the curve. 



The form of the steam temperature curve, figure 11, is also similar 

 to that showing the index of refraction. It rises nearly straight at first , 

 but turns abruptly toward the right at about 70 per cent. After 

 combining the interpretations of the several curves, it can be con- 

 cluded with safety that the oil consisted of 70 per cent of a substance 

 of uniform physical properties mixed with about 30 per cent of com- 

 plex heavier oils. The original sample was a yellowish red in color, 

 the fractions to 70 per cent were colorless and of a pine-like but not 

 sweet odor; from 70 to 80 per cent they were light yellow, and the 

 residue was red and rather strong smelling. These facts lead one to 

 believe that Turpentine No. 14 is rather poor in quality. However, 

 by suitable methods of refining 70 per cent of a high-grade product 

 could be made from it. 



TURPENTINE No. 27 A REFINED STEAM TURPENTINE. 

 Table 3 gives the data for a refined steam turpentine. 



TABLE 3. Turpentine No. 27 A refined steam turpentine. 

 [Specific gravity, 0.8608 at 15; index of refraction, 1.4709 at 15; weight taken 500 grams.] 



a About. 



[Cir. 152] 



